How to Raise and Harvest Trout for Aquaponics

When it comes to raising fish for Aquaponic systems, some fish are better than others. Trout are fast becoming the preferential fish in a Hydroponic system for a few reasons. One is the final product when harvested. Trout has great texture, color, and flavor and is delicious to eat. They can reach full plate size faster than any other fish used.

Silver Perch will take 3-4 years growth rate to reach that size. The best way to take advantage of growing Trout is to harvest them at their peak growing cycle. Before they start to decline. They start to decline at sexual maturation. Males start at about 1 year and females at about 2 years. Aquaponic farmers use 100 percent of females and harvest them before sexual maturation at 2 years.

They are also better to domesticate in the setting of hydroponics. After a few generations, through a Selection of certain fish, You can pick the ones that are better to breed, are lesser stressed, and are more resistant to normal problems that would affect their health. The trout become used to being handled by humans more so than other fish used in Hydropic systems.

Trout grow in clear clean and well-open gated water that is colder in temperature.  They are a good fit with Hydroponics and are hardier than you would think. Trout is fast becoming the more preferential tank fish used in systems today. Assuming that you know how Aquaponics systems work, this article will run the step-by-step process of using Trout in the system.

Starting with buying fingerlings, which are small young fish, and running them through the Basic Aquaponic system to creating a garden, and then harvesting these beautiful Rainbow Trout in a natural and sustainable process.


How to Raise and Harvest Trout for Aquaponics


The basics for getting your tanks ready for the process are the same with trout as with other fish. There are a few differences in temperatures and Dissolved Oxygen rates that need to be maintained in order for the fish to survive and thrive.

The Rainbow trout is a hardy fish that is easy to spawn and tolerant of a wide range of environments and handling. The Trout is capable of handling many different habitats surviving in fast-moving well-oxygenated streams to deep lakes.

The species can exist in a wide range of temperatures of 0-27 degrees centigrade where spawning will be best in a more narrow temperature of 10-14 degrees.

The optimum rate for a Rainbow Trout is around 21 degrees centigrade. Temperature and food availability influence a Trout’s growth and maturation, which usually is between 3 years. females are often to produce 2000 eggs per kg of body weight. some trout can mature early and produce even more spawn all year round.

Cross-breeding resistance to disease and bigger sizes is successful and even improves meat quality and taste. The pigment of the fish and its flesh can be altered with foods that are synthetically produced.

Feed for trout has been modified over the years and now processing of the food contains highly nutritious pellets for all stages of their growth stages. Feed ingredients of the food contain fish meal and grains but the use of fish meal has lessened over the last few years.

Reducing to lower than 50 percent with the addition of higher protein ingredients like soy. The foods are high energy and are broken down quickly by the Trout. Hand feeding can be done on smaller systems a few times of day with very small or very big fish. The pellets are made for all stages of growth and according to the size of the pellet and the size of the fish.

Negative impacts that affect other fish species-driven systems are basically the same as the Trout Aquaponic system.  Special care is given to the amount of fish and the condition of the water that is eventually delivered as nutrients to the crops being grown.

The feeding of the fish and the chemistry of the water will dictate the final product of fish and plant yield. A well-balanced system is a controlled and more productive system.

Fish waste in the tanks which in this case will be waste from Trout will be delivered by a pump to the Grow Beds where Media such as gravel or clay media contain colonies of Bacteria that convert the Trout waste from Ammonia to Nitrites to Nitrate that the Plants use as Food or Nutrients to grow.

By doing this, It cleans the water from the Tank that contains the fish waste which in turn keeps them in a healthy environment. A sustainable life cycle can only start with the addition of a handful of fish food pellets.

The only difference is the condition of the water that Trout will prefer over other species of fish, which will make them happy and keep them multiplying and healthy.

Dissolved Oxygen:

Important requirements for growing Trout in Aquaponic Systems are Higher Dissolved Oxygen(DO) in the contents of the tank water. Trout need higher levels than Catfish, Tilapia, or Perch, which are well-known fish normally used in the process. In a system that contains Trout, up to 7.0 ppm or mg per liter of oxygen levels are needed to maintain the health of the fish.

This is not a very complicated thing to do. In an aquarium, a small pump with an air stone on the end of the hose can deliver enough air through bubbles to maintain the aeration of the tank.


The other requirement is the Temperature of the water in the tank. Trout are cold-water fish that normally live in water in North America and Europe where their habitats never exceed 25 degrees Celsius temperatures.

Trout will start to struggle above 23 degrees Celsius and then die.  So with Trout, the tank needs to be adjusted between 18 and 23 degrees at all times. That is 64.4-73.4 degrees Fahrenheit range at all times in the tank. This will be the best condition where the fish will grow like crazy.

H2O Quality:

Trout needs good quality water that has good Filtration. We are talking about good Bio-filtration. The water needs attention to detail and levels of Ammonia-Nitrite and Nitrate need to be maintained as in a healthy Biological system.

The Aquaponic tanks need to be tested to ensure that the standards are being kept. Trout won’t accept Ammonia levels of more than 5ppm or mg/l that other Aquaponic fish would handle. They will start to stress and you would have a problem in your system.

Always try and keep those Nitrifying parameters low and monitor them regularly. If you start to see a trend of them coming up in concentrations, you need to take action fast to keep up the health of your fish.

Nutrient Levels are starting to rise in the Aquarium- Renew some of the water or Decrease the amount of fish in the Tank. Turn up the pump rate. This will drop the Ammonia rates back down to acceptable ppm readings and you will gain control of your tank again.

The systems in Aquaponics all work the same. Some fish just need a little more attention than others do. This also works on the Grow Bedside of the system.

If you are sending the plants too many nutrients, over the Levels of 50mg/l. or so.  You can adjust that level the same way. Adding more water to the system, will dilute higher levels of nutrients and bring back the balance for your control of the system. You can always use nutrient-rich water for other plants in your gardens.

Maximizing the cleanliness of the Trout’s water environment can be done by keeping the Trout’s size limited. It only takes 1 year for male Trout to reach maturation. When males reach maturation they secrete things into the water that are harmful and will eventually dirty the aquarium.

They also won’t convert food the same and the overall condition and size of the Trout are affected. This is unlike the Female Trout which will grow for two years until it reaches maturation.

Testing Your Aquaponic Tank:

Before adding your fingerlings to the Aquarium Tank you need to make certain that the Nitrogen Cycle is in place throughout your system. If it’s not right you will kill the Trout Fingerlings you just purchased.

For this, you need a reliable Test Kit or electronic Testers found here on MyWaterEarth&Sky and some knowledge of the Nitrogen Cycle. This process takes about 1 month to cycle the tank.

Follow these steps:

Start Cycling The Tank throughout the whole System. Pumping the Aquarium water through the Grow Beds and back again.

  1. Add a handful of good nutrient-rich fish food to the tank.
  2. After a week – Start Testing the Tank for Ammonia
  3.  After a few more days for Nitrites
  4.  After a few more Days Test for Nitrates.
  5. Continue testing for all three nutrients until they are all depleted.
  6.  What you will see is that the levels for each form of Nitrogen will peak first with Ammonia then Nitrites then Nitrate. As they break down and run through the system. Bacteria will build upon the Grow Bed Media and break down the Ammonia and Nitrites into Nitrates. Then the plants in the Grow Bed will use those Nitrates as food for Growth. When all the levels in the Aquarium Fish Tank are depleted and at 0 reading, then you are ready to add the fingerlings to the system. If you add them too early they will die or get sick. Nitrates and Nitrites can kill fish just as much as Ammonia.

*What this means is the Nitrogen from the tank was broken down properly to Nitrates and the plant is accepting the Nitrates as a food source.

After you feed the fish they will break down the food a little bit faster and your system is ready to rock & roll.


Growing Raising Trout and Other Fish Species


Feeding your Trout in the Aquaponic System:

Fish food is specially adapted to the needs of Trout and raising fish. Trout are true predators and need a certain amount of food made from fish in their diet. Aquaponics trout fish need a lot of protein to keep up with their growth rate in the short time that they are raised before they are harvested.

The food has certain ingredients that will keep Trout healthy and growing for that duration. They come in pellets and are sized appropriately for the ability of the fish to eat them. Here are other Feeding Rules:

  • When feeding your fish make sure that the food is spread out and evenly distributed across the top of the water in the tank.
  • Feed them twice a day, making sure that you don’t overfeed them or underfeed them.
  • The Fish Feed quality needs to be the best quality to ensure the proper growth and metabolism that will ensure the best health and taste of the Trout when it’s harvested.
  • The Fish should all be the same size. A farmer wilconstantly sort his fish according to the size of the fish. This will stop Territorial behavior and keep bigger fish from eating the smaller fish’s food.
  • Focus on keeping your fish at a size right before maturation. Not too big. It is the most productive and efficient way to farm Aquaponics using Trout.

Like other types of fish in Aquariums, some Trout is a dominant species and needs to be sized and grouped in the tank. They have a territorial type of behavior and it’s likely that if they are not mixed together properly in the same tank space one dominant Trout will control and even kill the other less dominant fish.

Others around him could get stressed and possibly die. Keep them in bigger numbers and size them fairly proportionately in size.

So it’s better to have a big population of Trout together than a smaller group of Trout living together. The reason is that in a larger group of different-sized fish, the fish form a society and tend not to recognize each other on a one-to-one basis.

The bigger Trout will have less of a tendency to become dominant over all the other size fish in the tank. Always make sure that you have enough Oxygen levels in the tank for the Trout.

If you don’t the fish will start to lose their appetite and their health will start to break down. You can add more plant life to your Grow Bed that could bump the levels of Oxygen up enough to maintain the systems’ health. Keep the fish eating and growing properly.

There is a symbiotic relationship between Aquaculture and Hydroponics and testing the system on a regular basis can give this modern farmer a  unique opportunity to observe this natural occurrence firsthand. The operator of the Aquaponic System needs to see the elements that drive this system in order to keep the delicate balance in control.

A Test Kit that tests for amounts of Ammonia-Nitrites -Nitrates and Dissolved Oxygen can make the difference between a wasted system or a successful Aquaponic System.

You want to make sure that the fish convert the lowest amount of energy you provide from food and Oxygen to the highest amount of growth and development that makes this system highly sustainable.

You can calculate the health of the whole system by the amount of Food to Fish ratio. In this case Trout. The ratio says that you used to say a quantity of 20 pounds of fish food in the first 2 months for 10 pounds of trout.

The conversion would be 20/10 then the feed ratio is 20 pounds of food divided by 10 pounds of Trout = The Feed Conversion Ratio = 2. If the food you are feeding your fish is not highly digestible then the quantity that you normally feed your fish will increase.

Try and feed the fish more times a day with the same amount. Sort your fish in case there is a dominant fish in the tank. Maintain Temperature and Oxygen levels. A good Food Conversion for Trout is 0.9 

This information will allow you to make adjustments to the system to either limit the feeding amount or even the kind of fish you may want to use in the next cycle.

In Aquaponics, if fish get sick there needs to be some other method to solve the problem without the use of pesticides or antibiotics to offset the disease. The whole idea and organic nature of the process are to avoid everything that is considered not natural. In big fish hatcheries, Trout can easily pick up disease through parasites and funguses that are typically found at these installations.

They can spread very fast-moving from fish to fish causing a lot of damage. The result is the use of chemicals that can treat large amounts of fish at one time.

This can happen in a smaller Aquaponic System like yours if the fish is stressed or the condition falls to less desirable conditions in the system. You can remove fish that are stricken with parasites and remove them from the system and give them an isolated salt bath where the parasites will fall off and the fish can be put back in the Aquarium with the rest of the population.

Trout are susceptible to some viruses even in colder water and some bacteria in warmer water. In Aquaponics, fish can be kept in lower densities. For ultimate control keep Oxygen levels high and Nutrient levels low in the Aquarium.


Breeding Trout in Aquaponics Fish Tank


It is very important in Aquaponics that you maximize fish production by controlling the size and age of the fish. When maturation takes over, the energy of the fish that was used for growth takes a backseat and slows down considerably. If the temperatures start to change outside in your tanks, that will affect the Trout, and the conversion of the food to energy and growth will begin to stop.

So you need to grow a fish that is native to the area that you live in to maintain the sustainability that you are looking to achieve. Trout can’t survive if the water temperature is too high.


Female Trout takes about 2 years to sexually mature and will continue to grow at a fast rate until then. Females will grow the most and the fastest between 1 and 2 years of age.

They will start producing eggs at the end of the 2-year maturation and this is when their body slows down and their growth stops. For this reason, It’s much more productive and efficient to harvest Trout before they come to maturation.

Smaller Female Trout will maximize growth in that time frame. It’s easier to buy the Trout fingerlings after each Harvest. You can buy Indoor Garden Aquaponic Systems that are ready to GO with LED lighting, along with everything you need to start through MyWaterEarth&Sky and Amazon for less money than you think. A 100-fingerling Female Trout for $125-150.00 dollars online raised to maturation and then Harvests for another 1-2 year cycle.


Water Temperature and Oxygen in Aquaponics Fish Tank


There are a few things to remember leading up to the Harvesting of your Trout in the fish tank.

When you are sizing and handling your fish Don’t ever touch them without wetting your hands first. Your hands and fingers can stick to the fish and damage it. Harvest nets that are used to move the fish around and in and out of the tank should be soft and smooth to protect the Trout from damage.

Hold fish from underneath the belly and head. Never through the gill, as this way will break blood vessels in the fish’s neck will lead to stress and eventually death.

Partially remove the water from the main fish tank while you’re harvesting the fish and pick out the biggest ones that you have in the system or all the fish from the system so you can replace them. The fish should all be around the same size and same age.

The harvesting is done with the fish’s stress levels in mind which can affect the quality of the fish that is being taken. For the best-tasting Trout, the fish is starved for 2 or 3 days prior to removal from the tank and the head should be left on the gutted fish.

You can change the fish tank water before the harvest to clean the fish out by refilling it with some fresh water while they are still alive.

They will flush the nutrient-filled water out themselves for better-tasting meat.  Trout can be kept for 10-14 days if the ice is right. They are a fine restaurant with highly prized food with tender and tasty flesh.

Pay Attention To Your Fish They Might Be Trying To Tell You Something

One of those warning signs fish can give you is skittishness. You walk past a tank and the fish nearly jump out. That skittishness. You’ll spot a fish doing odd things like banging up against the wall of the tank or gasping for oxygen at the surface of the water in the tank.

That’s a warning sign. They lose interest in feeding or act erratically rubbing their body on the bottom of the tank. That could be a parasite they are trying to get rid of. 

Checking your parameters for your tank water will tell you everything you need to know about the condition of the fish. Poor water quality is the most common problem attributed to stress. Parameters would be PH, Ammonia, Nitrites, Nitrates, and Dissolved Oxygen. Check it on a regular basis. you’ll see what the levels are in a healthy tank situation and then you’ll see bumps and peaks in the test results that will show an unhealthy tank situation.

The idea is that a closely monitored System will be a protection against an unhealthy system. Use your eyes and use your test kit. The low Oxygen content can be a number of things but is a critical test to let you know that something is wrong right now.

Sustainable food is an urgent task that is continuing to grow in leaps and bounds feeding today’s cities and urban areas with fresh wholesome organic food.

After Trout is Harvested in Aquaponics


Keeping your system clean benefits the fish and can add to the general health of the whole system. Feeding large schools of fish can be messy and pellets can end up on the bottom of the tank without being eaten. A simple tool like a plastic siphon can vacuum the waste on the bottom of the Aquarium and keep the tank contents from depleting oxygen. Organic material will deplete dissolved oxygen fast and eventually cause stress and risk to the health of the Trout.

After a Harvest is a Good Time to Clean the System

After you first Harvest, it’s a good time for you to clean out the whole system and pumps. They will eventually clog up and restrict flow which can affect Biomass, Plants, and Fish. Check your flow rate from the pump to make sure there are no obstructions inside.

The whole system is aerobic meaning that it is dependent on oxygen to make it all work. That includes the roots of the vegetables in the Grow Box and the Nitrifying bacteria that need oxygen to break down the Ammonia and Nitrites.

Keeping the system clean and after a Harvest, doing a more involved cleanup. Leaving the biomass on the media. Also, harvest fish that may infect or have a questionable appearance for the main reason of not affecting the rest of the school. Any fish that have some lesions or fin rot, get rid of them just in case.

The Plants in the system can easily be replaced but the fish in an Aquaponic system is harder to control and deal with. Spot the warning signs of fish stress. Stress just like in humans can lower your immune system and can make you sick, eventually killing you.

Recycled water-Hydroponics-Aquaponics and Sustainable methods of farming are critical to the future of generations on earth. We see it come to fruition on small scale. That’s very cool!



For more great articles on Aquaponics and Hydroponics like these just stay right here at MyWaterEarth&Sky-Taking a Hydroponic Garden to the next level is not as technical as you think. The language might be difficult to understand especially if the process is explained to you …………………………………………………….. Continue reading


JimGalloway Author/Editor



The world’s first commercial rooftop farm



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